Brio, zest (5)
I believe the answer is:
gusto
I believe this clue is a double definition.
'brio' is the first definition.
(thesaurus)
'zest' is the second definition.
(synonyms)
(Other definitions for gusto that I've seen before include "exhilaration" , "Verve, zest" , "ardour" , "Zest, exuberance" , "Zest and enjoyment in doing something" .)